The present disclosure pertains to systems and methods for supervising protective elements in electric power systems. In one embodiment, a system may be configured to selectively enable a protective action an electric power system. The system may include a data acquisition subsystem receive a plurality of representations of electrical conditions associated with at least a portion of the electric power delivery system. An incremental quantities module may calculate incremental quantities from the plurality of representations. The system may be configured to detect an event, to determine an incremental quantities value during the event, and to determine a time-varying threshold. The incremental quantities value during the event may be compared with the time-varying threshold, and a protective action module may be enabled to implement a protective action when the value of the incremental quantities value during the event exceeds the time-varying threshold.

The present disclosure pertains to systems and methods for supervising protective elements in electric power systems. In one embodiment, a system may be configured to selectively enable a protective action an electric power system. The system may include a data acquisition subsystem receive a plurality of representations of electrical conditions associated with at least a portion of the electric power delivery system. An incremental quantities module may calculate incremental quantities from the plurality of representations. The system may be configured to detect an event, to determine an incremental quantities value during the event, and to determine a time-varying threshold. The incremental quantities value during the event may be compared with the time-varying threshold, and a protective action module may be enabled to implement a protective action when the value of the incremental quantities value during the event exceeds the time-varying threshold.

A differential protection device monitors a first object to be protected in an electrical energy supply network. The differential protection device has a measuring unit configured to acquire measurement values at one end of the first object to be protected, a communication unit configured to exchange measurement values with a differential protection device arranged at another end of the first object to be protected, the communication unit has a physical interface for transmitting and receiving the measurement values, and an evaluation unit configured to form a differential value and to generate a fault signal indicating a fault with regard to the first object to be protected if the differential value exceeds a predefined threshold value. Ideally, the differential protection device is configured to monitor further objects to be protected and to exchange respective further measurement values with regard to each further object to be protected.

In a differential protection method for monitoring a line of a power grid, current indicator measured values are measured at the ends of the line and are transmitted to an evaluation device. A differential current value is formed with current indicator measured values temporally allocated to one another. The time delay between local timers of the measuring devices is used for the temporal allocation of the current indicator measured values measured at different ends. A fault signal indicating a fault affecting the line is generated if the differential current value exceeds a predefined threshold value. A check is carried out using electrical measured quantities temporally allocated to one another and a line-specific parameter to determine whether the time delay information indicates the actual time delay between the respective local timers. A time error signal is generated if erroneous time delay information is detected.

In a differential protection method for monitoring a line of a power grid, current indicator measured values are measured at the ends of the line and are transmitted to an evaluation device. A differential current value is formed with current indicator measured values temporally allocated to one another. The time delay between local timers of the measuring devices is used for the temporal allocation of the current indicator measured values measured at different ends. A fault signal indicating a fault affecting the line is generated if the differential current value exceeds a predefined threshold value. A check is carried out using electrical measured quantities temporally allocated to one another and a line-specific parameter to determine whether the time delay information indicates the actual time delay between the respective local timers. A time error signal is generated if erroneous time delay information is detected.

A photovoltaic power generation system includes a plurality of photovoltaic arrays, a plurality of shutdown units and an inverter. The shutdown unit is adjacent to the corresponding photovoltaic array, connected in parallel with the corresponding photovoltaic array, and electrically connected to the inverter via high voltage wires; the photovoltaic power generation system further includes a control unit configured to receive a detection signal indicating a state of the AC side of the inverter, monitor whether the AC side of the inverter is in a power-off state according to the detection signal, and generate a first power-off signal when the AC side of the inverter is in the power-off state; and the shutdown units are configured to receive the first power-off signal, and stop a power transmission from the photovoltaic arrays to the inverter according to the first power-off signal.

An integrated circuit-based nano-relay, comprising: an integrated circuit system of the nano-relay constructed according to an integrated circuit module built from a combinational logic circuit. An integrated power data processing algorithm is called by means of the integrated circuit module to perform signal processing on an input power signal, and power service data is output, that is, an integrated circuit is mainly constructed by means of the combinational logic circuit, the protection logic of the nano-relay is achieved by means of a hardware circuit module, and a response speed of the relay is improved.

A current consumed by an electric consumer is sampled as a first sampled current, and a main current sensor samples a current provided by an electric supply system as a second sampled current. A fault current detector detects a fault current between the electric supply system and the electric consumer, based on a non-zero difference between the first sampled current and the second sampled current and, in response, generates a circuit break signal. A residual current device receives the circuit break signal and, in response, to breaks a circuit between electric supply system and the electric consumer.

Disclosed is a fault monitoring method for a multi-port internal passive load-free probabilistic load flow (PLF) electric network. Current transformers are installed on the conductors. Currents from the current transformers are transformed into voltages, and the voltages are then converted into pulses by a voltage-to-frequency conversion (VFC) circuit. The pulses are transmitted via optical fiber to a comparison module, and an algebraic sum of all pulse counts is calculated. It is stipulated that when an installation direction of the current transformer is the same as a direction of the port pointing to the PLF electric network, the pulse count is positive, and when the installation direction of the current transformer is opposite to the direction of the port pointing to the PLF electric network, the pulse count is negative. When the algebraic sum exceeds a threshold, it is determined that a fault has occurred within the PLF electric network. This method is designed for an electric network where the direction of power transmission is uncertain, and can promptly and accurately detect whether faults such as single-phase grounding and interphase short-circuiting have occurred within the electric network. The method achieves advantages such as fast fault response, and precise and timely detection.

Disclosed is a fault monitoring method for a multi-port internal passive load-free probabilistic load flow (PLF) electric network. Current transformers are installed on the conductors. Currents from the current transformers are transformed into voltages, and the voltages are then converted into pulses by a voltage-to-frequency conversion (VFC) circuit. The pulses are transmitted via optical fiber to a comparison module, and an algebraic sum of all pulse counts is calculated. It is stipulated that when an installation direction of the current transformer is the same as a direction of the port pointing to the PLF electric network, the pulse count is positive, and when the installation direction of the current transformer is opposite to the direction of the port pointing to the PLF electric network, the pulse count is negative. When the algebraic sum exceeds a threshold, it is determined that a fault has occurred within the PLF electric network. This method is designed for an electric network where the direction of power transmission is uncertain, and can promptly and accurately detect whether faults such as single-phase grounding and interphase short-circuiting have occurred within the electric network. The method achieves advantages such as fast fault response, and precise and timely detection.